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IP subnet calculator

Type an address with its prefix or mask to see the network, its usable range and masks. Split it into smaller subnets, or look up any prefix in the reference tables.

Network164.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
164.0.0.0
Broadcast address
165.255.255.255
First usable
164.0.0.1
Last usable
165.255.255.254
Usable hosts
33,554,430 (33,554,432 less the network and broadcast addresses)
Subnet mask
254.0.0.0
Wildcard mask
1.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/7
Type
Public public
Old class
B (default /16)
As numbers
Hex A4000000 · Integer 2751463424 to 2785017855
Reverse DNS zones
164.in-addr.arpa
165.in-addr.arpa
/7 is not on a 8-bit boundary, so it takes 2 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10100100.00000000.00000000.00000000164.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network10100100.00000000.00000000.00000000164.0.0.0
Broadcast10100101.11111111.11111111.11111111165.255.255.255
Split into smaller subnets/16
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/13 (64)/14 (128)/15 (256)/16 (512)/17 (1,024)/18 (2,048)/19 (4,096)

164.0.0.0/7 makes 512 subnets of /16; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1164.0.0.0/16164.0.0.1 to 164.0.255.254164.0.255.25565,534
2164.1.0.0/16164.1.0.1 to 164.1.255.254164.1.255.25565,534
3164.2.0.0/16164.2.0.1 to 164.2.255.254164.2.255.25565,534
4164.3.0.0/16164.3.0.1 to 164.3.255.254164.3.255.25565,534
5164.4.0.0/16164.4.0.1 to 164.4.255.254164.4.255.25565,534
6164.5.0.0/16164.5.0.1 to 164.5.255.254164.5.255.25565,534
7164.6.0.0/16164.6.0.1 to 164.6.255.254164.6.255.25565,534
8164.7.0.0/16164.7.0.1 to 164.7.255.254164.7.255.25565,534
9164.8.0.0/16164.8.0.1 to 164.8.255.254164.8.255.25565,534
10164.9.0.0/16164.9.0.1 to 164.9.255.254164.9.255.25565,534
11164.10.0.0/16164.10.0.1 to 164.10.255.254164.10.255.25565,534
12164.11.0.0/16164.11.0.1 to 164.11.255.254164.11.255.25565,534
13164.12.0.0/16164.12.0.1 to 164.12.255.254164.12.255.25565,534
14164.13.0.0/16164.13.0.1 to 164.13.255.254164.13.255.25565,534
15164.14.0.0/16164.14.0.1 to 164.14.255.254164.14.255.25565,534
16164.15.0.0/16164.15.0.1 to 164.15.255.254164.15.255.25565,534
17164.16.0.0/16164.16.0.1 to 164.16.255.254164.16.255.25565,534
18164.17.0.0/16164.17.0.1 to 164.17.255.254164.17.255.25565,534
19164.18.0.0/16164.18.0.1 to 164.18.255.254164.18.255.25565,534
20164.19.0.0/16164.19.0.1 to 164.19.255.254164.19.255.25565,534
21164.20.0.0/16164.20.0.1 to 164.20.255.254164.20.255.25565,534
22164.21.0.0/16164.21.0.1 to 164.21.255.254164.21.255.25565,534
23164.22.0.0/16164.22.0.1 to 164.22.255.254164.22.255.25565,534
24164.23.0.0/16164.23.0.1 to 164.23.255.254164.23.255.25565,534
25164.24.0.0/16164.24.0.1 to 164.24.255.254164.24.255.25565,534
26164.25.0.0/16164.25.0.1 to 164.25.255.254164.25.255.25565,534
27164.26.0.0/16164.26.0.1 to 164.26.255.254164.26.255.25565,534
28164.27.0.0/16164.27.0.1 to 164.27.255.254164.27.255.25565,534
29164.28.0.0/16164.28.0.1 to 164.28.255.254164.28.255.25565,534
30164.29.0.0/16164.29.0.1 to 164.29.255.254164.29.255.25565,534
31164.30.0.0/16164.30.0.1 to 164.30.255.254164.30.255.25565,534
32164.31.0.0/16164.31.0.1 to 164.31.255.254164.31.255.25565,534
33164.32.0.0/16164.32.0.1 to 164.32.255.254164.32.255.25565,534
34164.33.0.0/16164.33.0.1 to 164.33.255.254164.33.255.25565,534
35164.34.0.0/16164.34.0.1 to 164.34.255.254164.34.255.25565,534
36164.35.0.0/16164.35.0.1 to 164.35.255.254164.35.255.25565,534
37164.36.0.0/16164.36.0.1 to 164.36.255.254164.36.255.25565,534
38164.37.0.0/16164.37.0.1 to 164.37.255.254164.37.255.25565,534
39164.38.0.0/16164.38.0.1 to 164.38.255.254164.38.255.25565,534
40164.39.0.0/16164.39.0.1 to 164.39.255.254164.39.255.25565,534
41164.40.0.0/16164.40.0.1 to 164.40.255.254164.40.255.25565,534
42164.41.0.0/16164.41.0.1 to 164.41.255.254164.41.255.25565,534
43164.42.0.0/16164.42.0.1 to 164.42.255.254164.42.255.25565,534
44164.43.0.0/16164.43.0.1 to 164.43.255.254164.43.255.25565,534
45164.44.0.0/16164.44.0.1 to 164.44.255.254164.44.255.25565,534
46164.45.0.0/16164.45.0.1 to 164.45.255.254164.45.255.25565,534
47164.46.0.0/16164.46.0.1 to 164.46.255.254164.46.255.25565,534
48164.47.0.0/16164.47.0.1 to 164.47.255.254164.47.255.25565,534
49164.48.0.0/16164.48.0.1 to 164.48.255.254164.48.255.25565,534
50164.49.0.0/16164.49.0.1 to 164.49.255.254164.49.255.25565,534
51164.50.0.0/16164.50.0.1 to 164.50.255.254164.50.255.25565,534
52164.51.0.0/16164.51.0.1 to 164.51.255.254164.51.255.25565,534
53164.52.0.0/16164.52.0.1 to 164.52.255.254164.52.255.25565,534
54164.53.0.0/16164.53.0.1 to 164.53.255.254164.53.255.25565,534
55164.54.0.0/16164.54.0.1 to 164.54.255.254164.54.255.25565,534
56164.55.0.0/16164.55.0.1 to 164.55.255.254164.55.255.25565,534
57164.56.0.0/16164.56.0.1 to 164.56.255.254164.56.255.25565,534
58164.57.0.0/16164.57.0.1 to 164.57.255.254164.57.255.25565,534
59164.58.0.0/16164.58.0.1 to 164.58.255.254164.58.255.25565,534
60164.59.0.0/16164.59.0.1 to 164.59.255.254164.59.255.25565,534
61164.60.0.0/16164.60.0.1 to 164.60.255.254164.60.255.25565,534
62164.61.0.0/16164.61.0.1 to 164.61.255.254164.61.255.25565,534
63164.62.0.0/16164.62.0.1 to 164.62.255.254164.62.255.25565,534
64164.63.0.0/16164.63.0.1 to 164.63.255.254164.63.255.25565,534
65164.64.0.0/16164.64.0.1 to 164.64.255.254164.64.255.25565,534
66164.65.0.0/16164.65.0.1 to 164.65.255.254164.65.255.25565,534
67164.66.0.0/16164.66.0.1 to 164.66.255.254164.66.255.25565,534
68164.67.0.0/16164.67.0.1 to 164.67.255.254164.67.255.25565,534
69164.68.0.0/16164.68.0.1 to 164.68.255.254164.68.255.25565,534
70164.69.0.0/16164.69.0.1 to 164.69.255.254164.69.255.25565,534
71164.70.0.0/16164.70.0.1 to 164.70.255.254164.70.255.25565,534
72164.71.0.0/16164.71.0.1 to 164.71.255.254164.71.255.25565,534
73164.72.0.0/16164.72.0.1 to 164.72.255.254164.72.255.25565,534
74164.73.0.0/16164.73.0.1 to 164.73.255.254164.73.255.25565,534
75164.74.0.0/16164.74.0.1 to 164.74.255.254164.74.255.25565,534
76164.75.0.0/16164.75.0.1 to 164.75.255.254164.75.255.25565,534
77164.76.0.0/16164.76.0.1 to 164.76.255.254164.76.255.25565,534
78164.77.0.0/16164.77.0.1 to 164.77.255.254164.77.255.25565,534
79164.78.0.0/16164.78.0.1 to 164.78.255.254164.78.255.25565,534
80164.79.0.0/16164.79.0.1 to 164.79.255.254164.79.255.25565,534
81164.80.0.0/16164.80.0.1 to 164.80.255.254164.80.255.25565,534
82164.81.0.0/16164.81.0.1 to 164.81.255.254164.81.255.25565,534
83164.82.0.0/16164.82.0.1 to 164.82.255.254164.82.255.25565,534
84164.83.0.0/16164.83.0.1 to 164.83.255.254164.83.255.25565,534
85164.84.0.0/16164.84.0.1 to 164.84.255.254164.84.255.25565,534
86164.85.0.0/16164.85.0.1 to 164.85.255.254164.85.255.25565,534
87164.86.0.0/16164.86.0.1 to 164.86.255.254164.86.255.25565,534
88164.87.0.0/16164.87.0.1 to 164.87.255.254164.87.255.25565,534
89164.88.0.0/16164.88.0.1 to 164.88.255.254164.88.255.25565,534
90164.89.0.0/16164.89.0.1 to 164.89.255.254164.89.255.25565,534
91164.90.0.0/16164.90.0.1 to 164.90.255.254164.90.255.25565,534
92164.91.0.0/16164.91.0.1 to 164.91.255.254164.91.255.25565,534
93164.92.0.0/16164.92.0.1 to 164.92.255.254164.92.255.25565,534
94164.93.0.0/16164.93.0.1 to 164.93.255.254164.93.255.25565,534
95164.94.0.0/16164.94.0.1 to 164.94.255.254164.94.255.25565,534
96164.95.0.0/16164.95.0.1 to 164.95.255.254164.95.255.25565,534
97164.96.0.0/16164.96.0.1 to 164.96.255.254164.96.255.25565,534
98164.97.0.0/16164.97.0.1 to 164.97.255.254164.97.255.25565,534
99164.98.0.0/16164.98.0.1 to 164.98.255.254164.98.255.25565,534
100164.99.0.0/16164.99.0.1 to 164.99.255.254164.99.255.25565,534
101164.100.0.0/16164.100.0.1 to 164.100.255.254164.100.255.25565,534
102164.101.0.0/16164.101.0.1 to 164.101.255.254164.101.255.25565,534
103164.102.0.0/16164.102.0.1 to 164.102.255.254164.102.255.25565,534
104164.103.0.0/16164.103.0.1 to 164.103.255.254164.103.255.25565,534
105164.104.0.0/16164.104.0.1 to 164.104.255.254164.104.255.25565,534
106164.105.0.0/16164.105.0.1 to 164.105.255.254164.105.255.25565,534
107164.106.0.0/16164.106.0.1 to 164.106.255.254164.106.255.25565,534
108164.107.0.0/16164.107.0.1 to 164.107.255.254164.107.255.25565,534
109164.108.0.0/16164.108.0.1 to 164.108.255.254164.108.255.25565,534
110164.109.0.0/16164.109.0.1 to 164.109.255.254164.109.255.25565,534
111164.110.0.0/16164.110.0.1 to 164.110.255.254164.110.255.25565,534
112164.111.0.0/16164.111.0.1 to 164.111.255.254164.111.255.25565,534
113164.112.0.0/16164.112.0.1 to 164.112.255.254164.112.255.25565,534
114164.113.0.0/16164.113.0.1 to 164.113.255.254164.113.255.25565,534
115164.114.0.0/16164.114.0.1 to 164.114.255.254164.114.255.25565,534
116164.115.0.0/16164.115.0.1 to 164.115.255.254164.115.255.25565,534
117164.116.0.0/16164.116.0.1 to 164.116.255.254164.116.255.25565,534
118164.117.0.0/16164.117.0.1 to 164.117.255.254164.117.255.25565,534
119164.118.0.0/16164.118.0.1 to 164.118.255.254164.118.255.25565,534
120164.119.0.0/16164.119.0.1 to 164.119.255.254164.119.255.25565,534
121164.120.0.0/16164.120.0.1 to 164.120.255.254164.120.255.25565,534
122164.121.0.0/16164.121.0.1 to 164.121.255.254164.121.255.25565,534
123164.122.0.0/16164.122.0.1 to 164.122.255.254164.122.255.25565,534
124164.123.0.0/16164.123.0.1 to 164.123.255.254164.123.255.25565,534
125164.124.0.0/16164.124.0.1 to 164.124.255.254164.124.255.25565,534
126164.125.0.0/16164.125.0.1 to 164.125.255.254164.125.255.25565,534
127164.126.0.0/16164.126.0.1 to 164.126.255.254164.126.255.25565,534
128164.127.0.0/16164.127.0.1 to 164.127.255.254164.127.255.25565,534
129164.128.0.0/16164.128.0.1 to 164.128.255.254164.128.255.25565,534
130164.129.0.0/16164.129.0.1 to 164.129.255.254164.129.255.25565,534
131164.130.0.0/16164.130.0.1 to 164.130.255.254164.130.255.25565,534
132164.131.0.0/16164.131.0.1 to 164.131.255.254164.131.255.25565,534
133164.132.0.0/16164.132.0.1 to 164.132.255.254164.132.255.25565,534
134164.133.0.0/16164.133.0.1 to 164.133.255.254164.133.255.25565,534
135164.134.0.0/16164.134.0.1 to 164.134.255.254164.134.255.25565,534
136164.135.0.0/16164.135.0.1 to 164.135.255.254164.135.255.25565,534
137164.136.0.0/16164.136.0.1 to 164.136.255.254164.136.255.25565,534
138164.137.0.0/16164.137.0.1 to 164.137.255.254164.137.255.25565,534
139164.138.0.0/16164.138.0.1 to 164.138.255.254164.138.255.25565,534
140164.139.0.0/16164.139.0.1 to 164.139.255.254164.139.255.25565,534
141164.140.0.0/16164.140.0.1 to 164.140.255.254164.140.255.25565,534
142164.141.0.0/16164.141.0.1 to 164.141.255.254164.141.255.25565,534
143164.142.0.0/16164.142.0.1 to 164.142.255.254164.142.255.25565,534
144164.143.0.0/16164.143.0.1 to 164.143.255.254164.143.255.25565,534
145164.144.0.0/16164.144.0.1 to 164.144.255.254164.144.255.25565,534
146164.145.0.0/16164.145.0.1 to 164.145.255.254164.145.255.25565,534
147164.146.0.0/16164.146.0.1 to 164.146.255.254164.146.255.25565,534
148164.147.0.0/16164.147.0.1 to 164.147.255.254164.147.255.25565,534
149164.148.0.0/16164.148.0.1 to 164.148.255.254164.148.255.25565,534
150164.149.0.0/16164.149.0.1 to 164.149.255.254164.149.255.25565,534
151164.150.0.0/16164.150.0.1 to 164.150.255.254164.150.255.25565,534
152164.151.0.0/16164.151.0.1 to 164.151.255.254164.151.255.25565,534
153164.152.0.0/16164.152.0.1 to 164.152.255.254164.152.255.25565,534
154164.153.0.0/16164.153.0.1 to 164.153.255.254164.153.255.25565,534
155164.154.0.0/16164.154.0.1 to 164.154.255.254164.154.255.25565,534
156164.155.0.0/16164.155.0.1 to 164.155.255.254164.155.255.25565,534
157164.156.0.0/16164.156.0.1 to 164.156.255.254164.156.255.25565,534
158164.157.0.0/16164.157.0.1 to 164.157.255.254164.157.255.25565,534
159164.158.0.0/16164.158.0.1 to 164.158.255.254164.158.255.25565,534
160164.159.0.0/16164.159.0.1 to 164.159.255.254164.159.255.25565,534
161164.160.0.0/16164.160.0.1 to 164.160.255.254164.160.255.25565,534
162164.161.0.0/16164.161.0.1 to 164.161.255.254164.161.255.25565,534
163164.162.0.0/16164.162.0.1 to 164.162.255.254164.162.255.25565,534
164164.163.0.0/16164.163.0.1 to 164.163.255.254164.163.255.25565,534
165164.164.0.0/16164.164.0.1 to 164.164.255.254164.164.255.25565,534
166164.165.0.0/16164.165.0.1 to 164.165.255.254164.165.255.25565,534
167164.166.0.0/16164.166.0.1 to 164.166.255.254164.166.255.25565,534
168164.167.0.0/16164.167.0.1 to 164.167.255.254164.167.255.25565,534
169164.168.0.0/16164.168.0.1 to 164.168.255.254164.168.255.25565,534
170164.169.0.0/16164.169.0.1 to 164.169.255.254164.169.255.25565,534
171164.170.0.0/16164.170.0.1 to 164.170.255.254164.170.255.25565,534
172164.171.0.0/16164.171.0.1 to 164.171.255.254164.171.255.25565,534
173164.172.0.0/16164.172.0.1 to 164.172.255.254164.172.255.25565,534
174164.173.0.0/16164.173.0.1 to 164.173.255.254164.173.255.25565,534
175164.174.0.0/16164.174.0.1 to 164.174.255.254164.174.255.25565,534
176164.175.0.0/16164.175.0.1 to 164.175.255.254164.175.255.25565,534
177164.176.0.0/16164.176.0.1 to 164.176.255.254164.176.255.25565,534
178164.177.0.0/16164.177.0.1 to 164.177.255.254164.177.255.25565,534
179164.178.0.0/16164.178.0.1 to 164.178.255.254164.178.255.25565,534
180164.179.0.0/16164.179.0.1 to 164.179.255.254164.179.255.25565,534
181164.180.0.0/16164.180.0.1 to 164.180.255.254164.180.255.25565,534
182164.181.0.0/16164.181.0.1 to 164.181.255.254164.181.255.25565,534
183164.182.0.0/16164.182.0.1 to 164.182.255.254164.182.255.25565,534
184164.183.0.0/16164.183.0.1 to 164.183.255.254164.183.255.25565,534
185164.184.0.0/16164.184.0.1 to 164.184.255.254164.184.255.25565,534
186164.185.0.0/16164.185.0.1 to 164.185.255.254164.185.255.25565,534
187164.186.0.0/16164.186.0.1 to 164.186.255.254164.186.255.25565,534
188164.187.0.0/16164.187.0.1 to 164.187.255.254164.187.255.25565,534
189164.188.0.0/16164.188.0.1 to 164.188.255.254164.188.255.25565,534
190164.189.0.0/16164.189.0.1 to 164.189.255.254164.189.255.25565,534
191164.190.0.0/16164.190.0.1 to 164.190.255.254164.190.255.25565,534
192164.191.0.0/16164.191.0.1 to 164.191.255.254164.191.255.25565,534
193164.192.0.0/16164.192.0.1 to 164.192.255.254164.192.255.25565,534
194164.193.0.0/16164.193.0.1 to 164.193.255.254164.193.255.25565,534
195164.194.0.0/16164.194.0.1 to 164.194.255.254164.194.255.25565,534
196164.195.0.0/16164.195.0.1 to 164.195.255.254164.195.255.25565,534
197164.196.0.0/16164.196.0.1 to 164.196.255.254164.196.255.25565,534
198164.197.0.0/16164.197.0.1 to 164.197.255.254164.197.255.25565,534
199164.198.0.0/16164.198.0.1 to 164.198.255.254164.198.255.25565,534
200164.199.0.0/16164.199.0.1 to 164.199.255.254164.199.255.25565,534
201164.200.0.0/16164.200.0.1 to 164.200.255.254164.200.255.25565,534
202164.201.0.0/16164.201.0.1 to 164.201.255.254164.201.255.25565,534
203164.202.0.0/16164.202.0.1 to 164.202.255.254164.202.255.25565,534
204164.203.0.0/16164.203.0.1 to 164.203.255.254164.203.255.25565,534
205164.204.0.0/16164.204.0.1 to 164.204.255.254164.204.255.25565,534
206164.205.0.0/16164.205.0.1 to 164.205.255.254164.205.255.25565,534
207164.206.0.0/16164.206.0.1 to 164.206.255.254164.206.255.25565,534
208164.207.0.0/16164.207.0.1 to 164.207.255.254164.207.255.25565,534
209164.208.0.0/16164.208.0.1 to 164.208.255.254164.208.255.25565,534
210164.209.0.0/16164.209.0.1 to 164.209.255.254164.209.255.25565,534
211164.210.0.0/16164.210.0.1 to 164.210.255.254164.210.255.25565,534
212164.211.0.0/16164.211.0.1 to 164.211.255.254164.211.255.25565,534
213164.212.0.0/16164.212.0.1 to 164.212.255.254164.212.255.25565,534
214164.213.0.0/16164.213.0.1 to 164.213.255.254164.213.255.25565,534
215164.214.0.0/16164.214.0.1 to 164.214.255.254164.214.255.25565,534
216164.215.0.0/16164.215.0.1 to 164.215.255.254164.215.255.25565,534
217164.216.0.0/16164.216.0.1 to 164.216.255.254164.216.255.25565,534
218164.217.0.0/16164.217.0.1 to 164.217.255.254164.217.255.25565,534
219164.218.0.0/16164.218.0.1 to 164.218.255.254164.218.255.25565,534
220164.219.0.0/16164.219.0.1 to 164.219.255.254164.219.255.25565,534
221164.220.0.0/16164.220.0.1 to 164.220.255.254164.220.255.25565,534
222164.221.0.0/16164.221.0.1 to 164.221.255.254164.221.255.25565,534
223164.222.0.0/16164.222.0.1 to 164.222.255.254164.222.255.25565,534
224164.223.0.0/16164.223.0.1 to 164.223.255.254164.223.255.25565,534
225164.224.0.0/16164.224.0.1 to 164.224.255.254164.224.255.25565,534
226164.225.0.0/16164.225.0.1 to 164.225.255.254164.225.255.25565,534
227164.226.0.0/16164.226.0.1 to 164.226.255.254164.226.255.25565,534
228164.227.0.0/16164.227.0.1 to 164.227.255.254164.227.255.25565,534
229164.228.0.0/16164.228.0.1 to 164.228.255.254164.228.255.25565,534
230164.229.0.0/16164.229.0.1 to 164.229.255.254164.229.255.25565,534
231164.230.0.0/16164.230.0.1 to 164.230.255.254164.230.255.25565,534
232164.231.0.0/16164.231.0.1 to 164.231.255.254164.231.255.25565,534
233164.232.0.0/16164.232.0.1 to 164.232.255.254164.232.255.25565,534
234164.233.0.0/16164.233.0.1 to 164.233.255.254164.233.255.25565,534
235164.234.0.0/16164.234.0.1 to 164.234.255.254164.234.255.25565,534
236164.235.0.0/16164.235.0.1 to 164.235.255.254164.235.255.25565,534
237164.236.0.0/16164.236.0.1 to 164.236.255.254164.236.255.25565,534
238164.237.0.0/16164.237.0.1 to 164.237.255.254164.237.255.25565,534
239164.238.0.0/16164.238.0.1 to 164.238.255.254164.238.255.25565,534
240164.239.0.0/16164.239.0.1 to 164.239.255.254164.239.255.25565,534
241164.240.0.0/16164.240.0.1 to 164.240.255.254164.240.255.25565,534
242164.241.0.0/16164.241.0.1 to 164.241.255.254164.241.255.25565,534
243164.242.0.0/16164.242.0.1 to 164.242.255.254164.242.255.25565,534
244164.243.0.0/16164.243.0.1 to 164.243.255.254164.243.255.25565,534
245164.244.0.0/16164.244.0.1 to 164.244.255.254164.244.255.25565,534
246164.245.0.0/16164.245.0.1 to 164.245.255.254164.245.255.25565,534
247164.246.0.0/16164.246.0.1 to 164.246.255.254164.246.255.25565,534
248164.247.0.0/16164.247.0.1 to 164.247.255.254164.247.255.25565,534
249164.248.0.0/16164.248.0.1 to 164.248.255.254164.248.255.25565,534
250164.249.0.0/16164.249.0.1 to 164.249.255.254164.249.255.25565,534
251164.250.0.0/16164.250.0.1 to 164.250.255.254164.250.255.25565,534
252164.251.0.0/16164.251.0.1 to 164.251.255.254164.251.255.25565,534
253164.252.0.0/16164.252.0.1 to 164.252.255.254164.252.255.25565,534
254164.253.0.0/16164.253.0.1 to 164.253.255.254164.253.255.25565,534
255164.254.0.0/16164.254.0.1 to 164.254.255.254164.254.255.25565,534
256164.255.0.0/16164.255.0.1 to 164.255.255.254164.255.255.25565,534

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.